In any web application, it's normal to have input data that alters a page. For example, a user may update their username, or submit a post. In vue, we can watch for these changes using watchers. Watchers allow us to check on a specific data element or prop and see if it's been altered in any way.
If you are brand new to Vue, get started with our guide on making your first Vue app here, before diving into watchers.